Effect of biofertilizer containing Thiobacillus bacteria along with different levels of chemical sulfur fertilizer on growth response and photochemical efficiency of small radish plants (Raphanus sativus L. var. shushtari) under greenhouse conditions

Abstract

Biofertilizers containing sulfur-oxidizing bacteria increase the accessibility of roots to nutrients by reducing soil pH. These biofertilizers can significantly contribute to soil fertility and increase plant growth. The present study was conducted to investigate the effect of a mixture of sulfur biofertilizer (SB) and granular sulfur fertilizer (GSF) on the growth, absorption of some elements, and photochemical efficiency of PSII in small Raphanus sativus grown in greenhouse conditions. GSF, including 0, 200, 400, and 600 kg ha−1 was added to the soil of the pots without or with biofertilizer containing Thiobacillus bacteria. The results showed that applying biofertilizer along with different levels of GSF increased the fresh weight and contents of anthocyanins, soluble sugars, starch, and some nutrients in leaves and swollen red roots. In addition, these treatments led to an increase in shoot length and photosynthetic pigments. In plants treated with a mixture of biofertilizer and chemical fertilizer, the photochemical efficiency of photosynthesis improved. The results of this study suggest the use of SB along with GSF (even at low and medium levels) can improve the growth and photosynthetic performance of radish plants in most of the measured indicators, at least in current experimental conditions. The results of this study can be significant for less use of chemical fertilizers and the production of agricultural products with higher food security, especially in developing countries.